Operating circuits for discharge lamps are known, which include a switched mode power supply which is coupled to a source of d-c energy, which may be supplied by a battery or, for example, by a rectifier from a power supply network. The voltage of the d-c energy source may vary. The switched mode power supply delivers d-c output energy changeable within wide limits; the d-c output power can be changed by an inverter circuit to a-c output if the lamp is to operate under alternating current conditions, or can be left as direct current if the lamp operates with direct current energy. An ignition circuit to start ignition of the lamp is interposed between the switched mode power supply and the inverter circuit or the lamp, respectively.